This invention relates to containers for holding consumable substances and more particularly, but not exclusively, to containers for holding carbonated liquids.
Carbonated drinks have been available for over a century, and it is a well recognised problem with them that when exposed to air for a significant amount of time or repeatedly, they tend to lose their fizz, i.e. go flat. As a result, such drinks have tended to be sold in small containers in quantities that can be drunk all at once. More recently however, larger containers, such as the one, two or even three liter bottle, have been used. Consequently the problem of the drink going flat has been brought to prominence, because the container is repeatedly opened and then reclosed in order to serve relatively small drink portions and then leave the remainder stored in the container. This repeated exposure to air of the stored drink tends to make the last servings of the drink go flat. Nevertheless, large containers are more economical to produce and easier to handle than the equivalent number of smaller containers. However, there is associated with them pressure on the consumer to empty the entire container all at once, because of the tendency of the last servings of the drink to go flat if the container is repeatedly opened and closed, as described hereinbefore.